It was a great experience, and I think I did acceptably well enough. I’d certainly love to do it again sometime, but since I won the spot in an auction at the SGU dinner during The Amazing Meeting 2012, I probably won’t have another opportunity. However, if the SGU team ever needs anyone to fill in on short notice in the future and they can’t find any heavy hitters to be on, this is a standing offer to be available for a guest spot in the future.

“So what about ram-jet like ships? probably quite useless (to vulnerable) as carriers for an invasion force, but they do not have the problem of carrying all that fuel with them.
also, of course, If we assume ET doesn’t want to spend 200 or more years making a round trip to Earth… doesn’t necessarily apply for ET’s with, eg., longer life spans than ours.”

Thanks, for the comment, speising. Basically, you’re talking about a Bussard Ram Jet. There’s a few problems associated with that.

You’d be scooping up hydrogen to use as a fusion fuel, but hydrogen’s not a particularly good fuel for fusion, believe it or not. The proton-proton chain, which is the primary source of energy production in stars less than 1.3 solar masses, is a very slow process (like an average of one billion years per reaction in the first step), which is a good thing otherwise the sun would have burned out after just a few million years.

You could theoretically use the CNO cycle for hydrogen fusion, but the confinement and cooling requirements would likely be insurmountable. We’re talking about temperatures and densities greater than that of the core of the sun.

Also, the interstellar medium isn’t as dense with hydrogen as Bussard thought it was, and you probably wouldn’t be able to scoop up enough fuel.

All this completely ignores the shielding requirements, which I never even went into in my earlier posts, mostly because I concluded interstellar travel was already impractical before even getting to the shielding requirements. Traveling at speeds even at one tenth the speed of light, every particle of dust floating in space is going to impact your space craft with a lot of kinetic energy.

Let’s assume a particle of cosmic dust floating in interstellar space with zero velocity relative to the Earth. Let’s also assume this particle is medium sized cosmic dust, say 300 micrometers in diameter, and let’s further assume it’s density is average for cosmic dust, 2.0 g/cm^3. This particle has a mass of only 2.82X10-8 kg or .028mg. If our vessel is traveling at 1/10th the speed of light relative to Earth, that particle of cosmic dust is going to impact our spacecraft with a kinetic energy of 12 Megajoules. To put that into perspective, lets assume a typical automobile mass of 1500kg (3300lb); that particle of dust is going to impact our spacecraft with the same kinetic energy as a car traveling at 454km/h (284mph). How are you going to protect against that kind of collision, and what do you do if you run into a particle that was 10 or 100 time larger? 300 micrometers is pretty small; a strand of human hair is 100 micrometers wide.

In regards to the other part of your comment,

“If we assume ET doesn’t want to spend 200 or more years making a round trip to Earth… doesn’t necessarily apply for ET’s with, eg., longer life spans than ours.”

I’ll just add that even if an alien species were to have a significantly longer life span that humans, it wouldn’t necessarily follow that their perception of the passage time or their value of time were different than ours. If science found a way to extend you lifespan to 1000 years, would you be interested in spending 200 years in a submarine without port if there was an alien planet at the end of the trip? I think 200+ years is still a long time, no matter how many years you have ahead of you in life.

A couple of months ago, I was flipping through channels on my POOP TV* and caught a few minutes of one of those really bad, direct to cable movies they run all the time on the Syfy channel. The movie was Savage Planet and before I changed the channel, I chanced to hear the following lines of dialog spoken by one of the characters in the movie:

“I always believed there had to be a scientific explanation for everything. Science was the only answer. Since I’ve been here, I’m rapidly becoming a skeptic.”

I hit the record button on my DVR remote so I could preserve that line of dialog for a potential future blog post. However, I didn’t continue watching the program, and I stopped the recording after the dialog, so I only have a few minutes recorded.

I don’t really know what the character was specifically talking about, but I imagine it had something to do with the killer space bears the reviews say the movie contains. Regardless, this quote is an epic fail on the part of the writers of the movie. They apparently buy into the philosophy that “science doesn’t know everything”, which is really a misunderstanding of science, since science is a process, and not a body of knowledge or answers.

“Science is a systematic enterprise of gathering knowledge about the world and organizing and condensing that knowledge into testable laws and theories.”

Science is not the answer, it is the means to an answer; it is they way to provide the explanation. If it is beyond your ability to explain scientifically, that is not a failure of science; that is a failure of your ability and knowledge base. Lacking a scientific explanation for a phenomenon does not make that phenomenon supernatural or paranormal, it simply means you haven’t found the scientific explanation yet. It can be very frustrating to not have the answer for something. It can be even more frustrating to know that the answer to that question may never be discovered during your lifetime, but that is no reason to engage in a god of the gaps fallacy and invent some supernatural explanation just so you can have an answer.

The dialog is also a profound misunderstanding of skepticism and the skeptical community. While the word skepticism can technically mean any questioning attitude, skepticism is about challenging claims lacking empirical evidence. It is also about challenging and examining the evidence that is used to support a claim. Skepticism is a crucible for inquiry in which claims are subjected to the fires of scientific scrutiny to burn away the extraneous fluff, leaving only scientific knowledge and/or more questions to be answered.

I don’t really expect any better for a low budget sci-fi movie that likely went straight to Syfy, but I wanted to blog about it because I’ve heard the “Science doesn’t have all the answers” gambit many times before, and I wanted to give my take on why that concept is so wrong.

*POOP TV: Picture Out Of Picture. I have a 40” HDTV sitting next to my 60” HDTV. When I was researching buying a new 60” HDTV, I wanted to get a model with PIP (Picture In Picture) because my then current TV had it, and it was pretty nifty for watching one football game while keeping track of another. I discovered that it would cost a lot more extra to get any of the current models with PIP, more than the cost of buying a second, smaller HDTV. So I bought a budget model 32” LCD TV to go next to my new 60” model. I found that I liked the setup not just for watching two football games at the same time, but also for watching TV while playing video games, especially when I am just performing some boring, repetitive action to level up a character, exploit a flaw in the game to generate endless amounts of money, or get some achievement. I liked the POOP TV setup so much that a couple years later, I sold my 32” TV to a friend and upgraded the POOP TV to a 40” model.

This post is part 3 of my Deconstruction of Stephen Hawking’s comments about contact with alien intelligences being risky. Part one was a general overview of why alien visitation/invasion is highly unlikely. Part two involved some rough numbers regarding the energy requirements for interstellar space travel at the near light speed velocities required to get anywhere in a remotely reasonable time frame.

In this post I will address the hypothetical “what if” scenario where some advanced alien intelligence has made a fundamental advance/ breakthrough in physics and engineering that allows interstellar or even intergalactic travel at effective speeds far in excess of the speed of light at a relatively low energy cost.

So, what if it is possible? What if the laws of physics as we know them need to be rewritten or at least get greatly expanded, and it turns out it is possible to travel interstellar distances in practical time frames instead of decades, centuries, or longer? Further, what if it is possible to do so with a relatively low energy cost instead of needing energy equivalent to tens of thousands of thermonuclear weapons or the yearly outputs of thousands of nuclear reactors?

Well, in short, in that case we’re probably screwed, and there’s still no reason to worry about it because there’s nothing we can do about it anyway.

Any alien civilization that advanced would probably be so far beyond us technologically that we probably couldn’t hope to resist their invasion or even evade detection by them. We’ve been making radio transmissions for well over 100 years, and during that time, our transmissions have been leaking into space to worlds more than 100 light years distant. I think it’s reasonable to speculate that any civilization capable of effectively superluminal travel is likely to have an equally advanced ability to detect and locate other intelligent civilizations or suitable worlds. If such a super advanced civilization is out there, and they are bent on conquest, they probably already have thousands or even millions of probes scattered throughout the galaxy looking for worlds to plunder in addition to their super advanced observation/ search techniques they will be using from their home world. Basically, if they are reasonably capable of getting here, they are probably capable of finding us whether we want them to or not.

Certainly, if they are capable of getting here, there can be little question of their ability to conquer us with little difficulty, as long as they’re not to worried about our welfare. Some might point to US and Soviet difficulties in Vietnam, Afghanistan, and Iraq as reasons to think we could have some hope of resisting a technologically superior invader, but I would disagree. First of all, the difference in technology would be closer to trying to fend off A-10’s with paper airplanes, the Ethiopians fighting off the Italian Army in 1935, or the Aboriginal Americans fighting off European invaders, settlers, or colonists. The Soviets did pretty well in Afghanistan until we started supplying the other side with modern military equipment. Our problems in Vietnam have been well documented and much debated, but I think it’s at least safe to say we weren’t engaged in an unrestricted attempt to eliminate North Vietnam’s military capability, and they had some help from the Soviets to boot. Likewise, we’re not attempting to eliminate the populations of either Afghanistan or Iraq. I’m pretty sure we could do that if we wanted to and we didn’t care about preserving the infrastructure. Independence Day may have been a fun movie, but it was delusional in regards to our ability to fight off an alien invasion. We very probably have little chance against a super advanced alien invasion force unless we can find some equally advanced alien allies or a fifth column to help us.

Additionally, Stephen Hawking seems to be implying that if we just stay silent, ET may not find us. This super advanced ET probably doesn’t need our help to find us. Irrespective of all the radio transmissions we’ve been leaking into space for over a hundred years, ET would probably be able to detect our rich blue and green world on their own without our help. We are already are able to detect planets only a few times more massive than the Earth orbiting other stars and detect elemental composition of stars with what would be extremely primitive techniques and technologies compare to what any superluminal civilization would have at its disposal. It seems likely that ET would be able to find our rich, garden world whether we were here to transmit to them or not.

In summary: If extraterrestrial aliens have the ability to get here in a reasonably short period of time without bankrupting their planetary economy, then they can probably find us, come here, and kick our butts if they want to.

Frankly, the fact that we haven’t yet been conquered by ET is a hint that maybe either ET isn’t interested in or capable of coming here and conquering us.

In this post, I will discuss the energy requirements of interstellar travel. Before I begin, I want to explain that I’m not going to show the math involved in the numbers, both because many people won’t be interested in the equations, and because this post is going to be long enough without showing all the calculations and equations involved. I’ve also ignored the time dilation factor which would reduce the relative travel time of the journey for the passengers of a spacecraft traveling close to the speed of light, but it only makes a significant difference at speeds that are energetically prohibitive anyway.

First, a discussion of the distances involved when discussing interstellar travel. To quote Douglas Adams’ Hitchhiker’s Guide to the Universe,

“Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it’s a long way down the road to the drug store, but that’s just peanuts to space.”

A typical galaxy is about 30,000 light years in diameter, the Milky Way being about 100,000 light years across. The distances between galaxies is even more mind bogglingly huge; the typical distance between galaxies is about 3 million light years. The visible universe is about 93 billion light years in diameter. (This is the current, commoving distance, not the distance at the time the light from the furthest visible stars was emitted.) So, to start, lets rule out intergalactic travel and focus on interstellar travel from within the Milky Way galaxy to see how practical that would be.

The nearest star to the sun is Proxima Centauri at a distance of about 4.2 light years, but Proxima Centauri is not a great candidate for habitual planets, for several reason. It’s a red dwarf, and that could pose numerous problems. It’s also variable, which almost closes the door on Proxima Centauri as a candidate for our hostile ET to come from. Moving on, there are 64 known stars within about 16 light years of the Earth, so let’s just say ET is coming from our back yard, say 10 light years away, though the aliens probably wouldn’t be so local unless life is very common in the universe.

So let’s look at how much energy it would take ET to get here from an unspecified plant 10 light years away. If we assume ET doesn’t want to spend 200 or more years making a round trip to Earth, they’re going to need to travel fast, really fast. Even 10% of the speed of light isn’t going to cut it. Let’s shoot for 90% of the speed of light (c). At .90 c, it’s going to take about 11 years to make the trip from ET world to earth, if ET can accelerate and decelerate nearly instantaneously.

So now we have our target speed, but we need to know the mass of ET’s vehicle. An object the size of the space shuttle (~110,000 kg for the orbiter by itself or around 2,000,000 kg for the whole system with boosters and fuel) seems a little physically small for an 11 year journey, so let’s try something a little bigger. A Virginia class submarine is about 8,000,000 kg and is a craft designed for long term endurance travel; let’s assume ET’s craft is the same mass.

The amount of energy needed to accelerate an object of a mass of 8,000,000kg to.90 c is 7.45 9.32 * 10^23 Joules, which is about 180 million megatons of energy. This is the equivalent of 3.6 ~4.5 million Tsar Bombas, the most powerful nuclear weapon ever detonated. It would take more than four five million kg of antimatter annihilating with the same amount of matter to produce this much energy. It’s worse than it looks, because the ETs need to slow down to a relative stop when they get here, which will take the same amount of energy as the acceleration, so we’re talking about 360 ~450 million megatons of energy just for a one way trip. But it’s even worse than that. We are ignoring the mass of the energy source and any propellant used in for ET’s spacecraft, and we are assuming 100% efficiency in the conversion of the energy source into vehicle velocity, which isn’t going to happen in the real universe. All things considered, without going into the increasingly complicated math (which would require us to start using calculus since the mass of the vehicle now decreases as we consume reactant & propellant), we probably need to increase our estimate of the energy requirements by an order of magnitude or so.

So, bottom line, at the end of our rudimentary estimate of the energy requirements to travel at .90 c, we’re talking about an energy requirement in the order of a billion megatons or so.

OK, what if ET is a little more patient and is willing to endure a 200 year round trip at .10 c? The energy requirements drop to ~17,000 ~870,000 Megatons of energy (or 17,000 Tsar Bombas) for a one way trip. (It’s not a linear decrease because we’re talking relativistic mechanics here.)

So, in summary, the energy requirements are massive for velocities even 10% of the speed of light, and absurdly huge for speeds 90% of c, and even at those speeds, we are limited to about 10 light years of distance for any reasonable length journey. Why would any ET, no matter how conquest driven they were, bother expending such energy resources to plunder the resources of another world, assuming they could even find a suitable planet to plunder in their local stellar neighborhood?

I think we can sleep soundly at night, never having to worry about Stephen Hawking’s ETs ever attacking the Earth ID4 style.

In regards to the energy requirements of some mythological faster than light propulsion system, who can really say what those would be? I can speculate that they would be much greater than those of traveling at velocities at “significant” percentages of the speed of light, and someone else can say that as long as we are speculating about faster than light travel, why can’t we speculate about some relatively low energy process to achieve those speeds? It’s all wild speculation if not outright fantasy at that point, so there’s really no numbers to talk about.

(And here is where I dare to Cordially Deconstruct the position of someone who is much, much, much smarter than I am)

There’s something on the order of 100 billion galaxies in the known universe, and there’s something on the order of 100 billion stars in each of those galaxies. We’re just beginning to scratch the surface of figuring out how many of those stars might contain planets and how many of those planets or their moons might be remotely habitable by life as we know it. I think it would be wise to assume that some forms of extremophiles could survive on worlds more hostile than what we conservatively call habitable. And although we don’t really have any reasonable clue for estimating the probability of life arising on a suitable world, let alone the odds of intelligent life developing, 10,000 billion, billion stars is a lot of stars (10^20), and that’s a lot of spins on the roulette wheel of life to hit the jackpot only once. In the absence of actual data, it seems reasonable to speculate that there’s life elsewhere in the universe, and some of it is probably more advanced than we are.

That being said, it also seems likely to me that inter-galactic space travel isn’t particularly likely, and we don’t have to worry about whether ET is friendly or not.

You may think this is modern arrogance, but despite mysteries like dark energy and dark matter, we have a pretty good idea of how the universe works, and it looks like the universal speed limit (can not obtain) for things with mass is the speed of light. The practical effect of this limit is that inter-galactic travel would take an incredibly long time to get anywhere not in you own star system. Intergalactic travel would also take an impractically large amount of energy if you wanted to travel at any velocity approaching a significant percentage of the speed of light. Even if we speculate the discovery of some way to travel faster than the speed of light, it seems reasonable to also speculate it would extremely (prohibitively) energy intensive.

So what might we have here in an ultra-advanced, space faring, alien species? We have ETs that have no motivation to travel to other stars for anything other than esoteric knowledge gathering that probably won’t be of any use to the folks back home anyway, since they’ll likely all be long dead by the time the explorers got back. Listen, if you have the energy resources to travel across the galaxy (either at sub-light or superluminal velocity), you don’t need to plunder the resources of other worlds; you’ve got resources coming out of your ying tang, and you’ve got the technology to do whatever you need with those resources. You’d be better off just terraforming some reletively nearby world rather than traveling across the galaxy to plunder a distant Earth-like planet.

Traveling across the galaxy to plunder the Earth’s resources would be like me driving to Alaska from Missouri to buy gas if my local filling station ran out. Why bother if I already have the resources to get there?

There’s just no science to support the hypothesis that cell phone use can cause cancer: There’s no biological science to show a mechanism for cell phone use to cause cancer, and there’s no observational science to show cell phone use correlates to an increased risk of cancer.

What we have instead is an unsupported and mostly implausible hypothesis that because non-ionizing radio frequency radiation from cell phones causes measurable biological effects and ionizing radiation can cause cancer, that cell phones probably cause cancer. Give that to a politician who cares more about being seen to act on what is perceived to be (or can be promoted as) an important issue than they do about being genuinely productive (or about taking the time to properly educate themselves on an issue before acting), and you get proposals for new, unneeded, unscientific laws.

Indoor light is non-ionizing electromagnetic radiation with far more energy than the radio frequency radiation of cell phones, and it too produces measurable biological effects, but nobody seems to be proposing cancer warnings on light bulbs. Oh, snap! … Never mind, set your hair on fire and run for the hills.

It was a well written article. It presented the facts objectively, didn’t cherry pick details to support an agenda or skew the story, and made no unsuported conclusions. Additionally, the conclusions that were drawn were very reserved and reasonable.

Points made in the article:

-Numbers of incidence of multiple myeloma in the sample are tiny.

-Numers of incidence are within predicted parameters, but high for one age group in question.
(8 cases, but 4 under 45: should only be 1 under 45)

-Timing is in question as research show that not enough time had passed for multiple myeloma to develope due to environmental exposeure to a carcinogen, suggesting a non-causal relationship to 9/11.

I was even more surprised to learn from Googling his name that David Caruso does not appear to be a dedicated science reporter. Maybe there’s hope for mainstream science reporting these days after all, even from non science reporters.

I though that Mr. Caruso deserved a Kudo for the kind of quality repoting that is increasingly rare these days: Way to go David! 🙂

Nearly all my favorite bloggers will be there, and the concentration of such blogging talent in one place could cause Las Vegas to collapse into an internet black hole!

I see the high temperatures in Las Vegas are supposed to be between 102F & 107F from today through Sunday. Whose bright idea was it to hold a conference in Las Vegas in July? Well, I suppose it will be a dry heat, but then again, so is an oven.